Weak Dy^III–Dy^III Interactions in Dy^III–Phthalocyaninato Multiple-Decker Single-Molecule Magnets Effectively Suppress Magnetic Relaxation

The DyIII quintuple-decker complex DyCdCdDy and hetero quadruple-decker complex DyCdY were synthesized, and their magnetic properties were compared with those of the quadruple-decker complex DyCdDy. Single-crystal X-ray analysis revealed that the coordination geometries around the DyIII ions of DyCdCdDy, DyCdY, and DyCdDy were similar. dc (direct current) magnetic measurements indicated that DyCdCdDy had very weak ferromagnetic DyIII–DyIII interactions but DyCdY did not. From a comparison of the magnetic relaxation times (τ) of the three complexes, the τ values of DyCdCdDy and DyCdDy, which have weak DyIII–DyIII interactions, are longer than that of DyCdY. In other words, weak DyIII–DyIII interactions effectively suppress magnetic relaxation.